The present invention relates to a reinforced veneer sheet and a method of manufacturing the same placing a length of cord into embedding engagement with the veneer sheet by forcing the cord through cuts formed across the veneer grain with spacings therebetween.
In general, logs contain a number of cracks created by internal stress imbalance caused during the lumbering or drying steps. If such logs are subjected to a cutting operation on a veneer lathe, cut-off veneer sheets are frequently imperfect. Moreover, such sheets are so susceptible to external forces that they fragment due to development of the cracks or creation of new cracks during the subsequent processes including trimming and transporting.
Such veneer sheet fragments reduce the plywood quality and yield in plywood production.
In order to solve the above-mentioned problems, a number of proposals have been made. For example, the Japanese Patent Application Publication No. 51-1764 titled "A method of joining veneer sheets and apparatus therefor" discloses a technique of forming cuts into butt ends of the sheet and burying a length of cord into each cut to reinforce the veneer sheet. This method cannot apply to thin veneer sheets. The Japanese Patent Application Publication No. 33-6498 shows a method of forming straight wedge-formed cuts in the veneer surface and embedding a length of water or adhesive-impregnated cord therein. There is also proposed by the Japanese Patent Application Publication No. 51-151311 a method of joining wet veneer sheets by a length of cord that includes a step of forming streaks of slant cuts in the sheet for inbedding cords and by the Japanese Patent Application Provisional Publication No. 53-18706 wherein a joined veneer sheet is manufactured by the method of the Japanese Patent Application Publication No. 51-151311. However, these methods have drawbacks in that the formed cuts extend over a substantial distance, offsetting the reinforcing effect and ineffective adhesives are used.